GOP's Wiley: Kohl Challenger "By the end of March"

So far, Robert Lorge and one Mr. Reddick have announced as GOP candidates to challenge Senator Herb Kohl. Few see them as serious contenders, however.

Well, last night, in a story on Kohl getting interrupted in Madison by protesters, a reporter got comment from the state GOP about the prospect of a serious contender from the right. Tagged onto the very end of a State Journal piece was this little tidbit:
Rick Wiley, executive director of the state Republican Party, said the GOP expects to have a challenger to Kohl in the race by the end of March.
Who will it be? Tim Michels? Tommy Thompson? Mark Neumann?

The rather specific timing Wiley gives makes me wonder if it isn't Tommy and folks are just waiting to utilize the impact of a sudden splash.